1. Field of the Invention
The present invention relates to a method for processing a semiconductor wafer, and more particularly to a method for cleaning a surface of a semiconductor wafer after chemical mechanical polishing.
2. Description of Related Art
In the semiconductor processing industry, chemical mechanical polishing (CMP) is known as one of the best techniques for planarizing and polishing a surface of a semiconductor wafer. CMP generally involves a polishing slurry composition which often contains abrasive particles such as silica and alumina in an acidic or basic solution. Typically, an aqueous solution is used to remove the particles and contaminants away from the surface after the CMP is completed. For instance, U.S. Pat. No. 6,537,381 discloses a method for cleaning and treating a semiconductor wafer after CMP. An improved cleaning chemical (ICC) is applied in the method. The ICC solution preferably includes ammonium hydroxide (NH4OH), ethylenediaminetetraacetic acid (EDTA), hydrogen peroxide (H2O2) and deionized water. The method includes at least four steps, and is complex and inconvenient to implement. It is also expensive since a multitude of devices and chemical reagents must be used.
U.S. Pat. No. 6,364,744, entitled “CMP System and Slurry for Polishing Semiconductor Wafers and Related Method,” discloses a method for chemical mechanical polishing a semiconductor wafer including metal. The method includes the steps of: providing relative movements between a semiconductor wafer and a polishing article; providing light to an interface between the polishing article and the semiconductor wafer; and delivering a slurry to the interface between the semiconductor wafer and the polishing article. The slurry preferably includes abrasive particles and at least one photocatalyst which are utilized to enhance oxidation of the metal in the semiconductor wafer.
However, the photocatalyst is only used during the CMP, in order to enhance oxidation of the metal in the semiconductor wafer. A plurality of particles and contaminants remained on the interface after the CMP. Consequently, the semiconductor wafer still needs to undergo cleaning treatment.